Method for producing fluorine-containing compound

The present invention provides an economically advantageous method for efficiently producing a fluorine-containing compound while ensuring high conversion of the starting compound, reducing production of 245cb, and reducing equipment costs and energy costs. Specifically, the present invention provides a method for producing a fluorine-containing compound represented by Formula (3): CF3CFYnCH2Zn (wherein n is 0 or 1, one of Y and Z is H, and the other is F or Cl) by successively reacting at least one chlorine-containing compound selected from the group consisting of chlorine-containing fluoroalkane represented by Formula (1): CX3CHClCH2Cl (wherein X is independently F or Cl, with the proviso that at least one X is F) and chlorine-containing fluoroolefin represented by Formula (2): CX3CCl═CH2 (wherein X is independently F or Cl, with the proviso that at least one X is F) with anhydrous hydrogen fluoride in the presence of a fluorination catalyst, wherein the concentration of hydrogen chloride in a reactor inlet gas is not less than 0.01 vol % and not more than 10 vol %.